Suddenly, the No. 1 team in the country looked vulnerable.
Yet here they are, still unbeaten, and with still more tough games to play.
McCoy passed for 391 yards and two touchdowns Saturday, but the Longhorns defense needed to come up with two huge stands in a 28-24 win over No. 7 Oklahoma State after he threw a third-quarter interception and fumbled late in the fourth.
"We're not going to beat everybody by 50 or 60," Texas cornerback Ryan Palmer said. "We showed we can dig down and fight."
Texas led 28-21 when McCoy threw the interception -- his first in 101 pass attempts over the past four games -- and the Cowboys seemed to have stolen all the momentum with the ball near midfield.
Instead of allowing a touchdown, Texas held them to a field goal. And when McCoy fumbled as he was swarmed by three defenders at the Cowboys 10 late in the fourth, Texas didn't allow them to get past their own 30.
Texas fans have watched McCoy play with near-perfect precision -- especially while beating Oklahoma and Missouri the previous two weeks -- and the turnovers seemed to stun the crowd of 98,515 fans.
"No one plays this game perfect," said wide receiver Jordan Shipley, McCoy's roommate who was also his favorite target with 15 catches for 168 yards.
Texas (8-0, 4-0 Big 12) got its third win in a row over a ranked opponent and it was the toughest by far. Texas beat Oklahoma 45-35 in Dallas with a big rally and used a 35-point first half to swamp Missouri in a rout at home.
The win over Oklahoma State (7-1, 3-1) sets up yet another big game next Saturday night at No. 8 Texas Tech.
"Our reward is Tech won 63-21 (over Kansas)," Longhorns coach Mack Brown said. "We've still got some work to do."